From: Ivan Vecera <ivecera@redhat.com> Date: Tue, 22 Jul 2008 09:13:50 +0200 Subject: [scsi] ST: buffer size doesn't match block size panics Message-id: 488588AE.4080101@redhat.com O-Subject: Re: [RHEL5 PATCH] ST Driver causing kernel panic condition Bugzilla: 443645 RH-Acked-by: Alan Cox <alan@redhat.com> RH-Acked-by: Vivek Goyal <vgoyal@redhat.com> >>> Description: >>> Kernel panic occurs when commands like tar are used with tape drives in fixed block >>> mode with buffer sizes that are not a multiple of the already formatted tape's block >>> size. >>> >>> Upstream status: >>> http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=9abe16c670bd3d4ab5519257514f9f291383d104 >>> > diff --git a/drivers/scsi/st.c b/drivers/scsi/st.c index 7f669b6..cb40dee 100644 --- a/drivers/scsi/st.c +++ b/drivers/scsi/st.c @@ -9,7 +9,7 @@ Steve Hirsch, Andreas Koppenh"ofer, Michael Leodolter, Eyal Lebedinsky, Michael Schaefer, J"org Weule, and Eric Youngdale. - Copyright 1992 - 2005 Kai Makisara + Copyright 1992 - 2007 Kai Makisara email Kai.Makisara@kolumbus.fi Some small formal changes - aeb, 950809 @@ -17,7 +17,7 @@ Last modified: 18-JAN-1998 Richard Gooch <rgooch@atnf.csiro.au> Devfs support */ -static const char *verstr = "20050830"; +static const char *verstr = "20070203"; #include <linux/module.h> @@ -1168,6 +1168,7 @@ static int st_open(struct inode *inode, struct file *filp) STps = &(STp->ps[i]); STps->rw = ST_IDLE; } + STp->try_dio_now = STp->try_dio; STp->recover_count = 0; DEB( STp->nbr_waits = STp->nbr_finished = 0; STp->nbr_requests = STp->nbr_dio = STp->nbr_pages = STp->nbr_combinable = 0; ) @@ -1397,9 +1398,9 @@ static int setup_buffering(struct scsi_tape *STp, const char __user *buf, struct st_buffer *STbp = STp->buffer; if (is_read) - i = STp->try_dio && try_rdio; + i = STp->try_dio_now && try_rdio; else - i = STp->try_dio && try_wdio; + i = STp->try_dio_now && try_wdio; if (i && ((unsigned long)buf & queue_dma_alignment( STp->device->request_queue)) == 0) { @@ -1596,7 +1597,7 @@ st_write(struct file *filp, const char __user *buf, size_t count, loff_t * ppos) STm->do_async_writes && STps->eof < ST_EOM_OK; if (STp->block_size != 0 && STm->do_buffer_writes && - !(STp->try_dio && try_wdio) && STps->eof < ST_EOM_OK && + !(STp->try_dio_now && try_wdio) && STps->eof < ST_EOM_OK && STbp->buffer_bytes < STbp->buffer_size) { STp->dirty = 1; /* Don't write a buffer that is not full enough. */ @@ -1766,7 +1767,7 @@ static long read_tape(struct scsi_tape *STp, long count, if (STp->block_size == 0) blks = bytes = count; else { - if (!(STp->try_dio && try_rdio) && STm->do_read_ahead) { + if (!(STp->try_dio_now && try_rdio) && STm->do_read_ahead) { blks = (STp->buffer)->buffer_blocks; bytes = blks * STp->block_size; } else { @@ -1945,10 +1946,12 @@ st_read(struct file *filp, char __user *buf, size_t count, loff_t * ppos) goto out; STm = &(STp->modes[STp->current_mode]); - if (!(STm->do_read_ahead) && STp->block_size != 0 && - (count % STp->block_size) != 0) { - retval = (-EINVAL); /* Read must be integral number of blocks */ - goto out; + if (STp->block_size != 0 && (count % STp->block_size) != 0) { + if (!STm->do_read_ahead) { + retval = (-EINVAL); /* Read must be integral number of blocks */ + goto out; + } + STp->try_dio_now = 0; /* Direct i/o can't handle split blocks */ } STps = &(STp->ps[STp->partition]); diff --git a/drivers/scsi/st.h b/drivers/scsi/st.h index 05a5cae..5857543 100644 --- a/drivers/scsi/st.h +++ b/drivers/scsi/st.h @@ -117,7 +117,7 @@ struct scsi_tape { unsigned char cln_sense_value; unsigned char cln_sense_mask; unsigned char use_pf; /* Set Page Format bit in all mode selects? */ - unsigned char try_dio; /* try direct i/o? */ + unsigned char try_dio; /* try direct i/o in general? */ unsigned char c_algo; /* compression algorithm */ unsigned char pos_unknown; /* after reset position unknown */ int tape_type; @@ -168,6 +168,7 @@ struct scsi_tape { #endif struct gendisk *disk; struct kref kref; + unsigned char try_dio_now; /* try direct i/o before next close? */ }; /* Bit masks for use_pf */